Single lever controls are well known and widely used in the art. For example, the owner hereof sells single-lever control of this type, as shown by Ultraflex catalog, pages 23 to 32, year 2008. The rocking lever controls a rocker arm via the supporting arm and a transmission system, which rocker arm has at its two ends a drive cable connected thereto, to transmit the angular displacement of the rocker arm to the member for switching the motion transmission state of the reversing gear, which may also be, for instance, a rocker arm keyed to motion reversal mechanisms control shaft.
When the lever is in a neutral position, the rocker arm is in a position in which the reversing gear is in an idle state, with motion transmission between the drive shaft and the propeller shaft being prevented. Starting from said neutral angular position, the initial angular displacement of the lever in a first direction and in a direction opposite to the former first causes a corresponding pivotal motion of the rocker arm, and said displacement stroke is transmitted by the cables to the actuator of the reversing gear which is thus switched into a state in which the engine shaft motion is transmitted to the propeller shaft with the two shafts rotating in the same direction and into a state in which the engine shaft motion is transmitted to the propeller shaft with said two shafts rotating in different, i.e. opposite directions. This corresponds to the forward and reverse gear of the boat. During said initial angular displacement stroke of the lever in either direction, the engine is maintained at idle speed, i.e. in a throttle condition in which the drive shaft runs a minimum number of revolutions. This allows the reversing gear to be switched from its idle state into the forward gear or reverse gear or from the forward gear directly into the reverse gear or vice versa, without being damaged, i.e. avoiding the damages that it might incur if the engine were in an accelerated state, with the drive shaft rotating at a high rpm.
Once the reversing gear has reached its switched state, any further stroke of the control lever is converted into an engine acceleration control, i.e. an increase of fuel or fuel-air mixture delivery.
It is apparent from the above that high accuracy is required of the transducers that convert the angular position of the control lever and the angular displacement thereof, and that position detection must be repeatable, i.e. not subject to drifts caused by inaccurate conversion of the position or motion into electric signals. In case of inaccurate correlation of the angular position or stroke of the lever to the generated electric signal, there may be no correct synchronism between the mechanical control of the reversing gear and the acceleration state, i.e. the number of revolutions of the above described engine.
This drift in the correlation of the angular position or stroke of the lever to the electric signal may be caused by excessive transducer tolerances or inaccuracies and clearances in angular motion transmission from the control lever to the transducer.
Such problems cannot be obviated by simply using more accurate, and accordingly more expensive transducers. Therefore, even with higher transducer accuracy, there will be no increase in the accuracy of control lever position reading and transmission and no repeatability of said position detection, and synchronism with the reversing gear position and control cannot be perfectly maintained.